U.S. Pat. Nos. 4,540,457, 4,566,981, 4,426,466, and 4,468,527 describe fluorine system water- and oil-repellent agents comprising, as a main component, units derived from a perfluoro-oxyalkyl-containing (meth)acrylate. However, these water- and oil-repellent agents gives a poor continuation property of water- and oil-repellency effect, and have a poor water- and oil-repellency-giving effect to a hydrophilic fiber such as cotton or silk.
U.S. Pat. No. 4,215,205 describes fluorine system water- and oil-repellent agents comprising a perfluorooxyalkyl-containing (meth)acrylate added with carbodiimide. However, although this water- and oil-repellent agent has a better water- and oil-repellency-giving effect to hydrophilic fibers, it is not yet sufficient, and this agent gives a poor continuation property of water- and oil-repellency effect.
Japanese Unexamined Patent Publication (Kokai) No. 5-222149 describes a water-repellent composition comprising a copolymer of at least three monomer comprising polyfluoroalkyl-containing (meth)acrylate, urethane bond containing poly(meth)acrylate, and blocked isocyanate containing (meth)acrylate, and blocked polyisocyanate compound. However, since this composition uses a blocked isocyanate, and this has a decomposition temperature of not less than 120.degree. C., so that this composition must be treated at a high temperature, which often injures fibers, this composition can substantially not be used. Further, since this composition also has a high possibility of damaging feeling of fibers, it cannot be used as a fiber treating agent.
Japanese Examined Patent Publication No. 58-1751 discloses that a copolymer of methyl methacrylate and 4-methacryloxy ethyl trimellitic acid can be an excellent adhesive for teeth. This document, however, does not describe to use 4-methacryloxy ethyl trimellitic acid for water- and oil-repellent agents, or to copolymerize it with polyfluoroalkyl-containing (meth)acrylate.